Supercomputers and other large computer systems typically include a large number of computer cabinets arranged in close proximity to each other. FIG. 1, for example, illustrates a portion of a prior art supercomputer system 100 having a plurality of computer cabinets 110 arranged in a bank. The computer cabinets 110 are arranged in a bank to conserve floor space and increase computational speed by reducing cable lengths between cabinets. Each of the computer cabinets 110 includes a plurality of computer module compartments 118 (identified individually as a first module compartment 118a, a second module compartment 118b, and a third module compartment 118c). Each module compartment 118 holds a plurality of computer modules 112. Each computer module 112 can include a motherboard electrically connecting a plurality of processors, memory modules, routers, and other microelectronic devices together for data and/or power transmission. Like the computer cabinets 110, the computer modules 112 are also positioned in close proximity to each other to conserve space and increase computational speed.
Many of the electronic devices typically found in supercomputers, such as fast processing devices, can generate considerable heat during operation. This heat can damage the device and/or degrade performance if not dissipated during operation. To dissipate this heat and maintain device temperatures at acceptable levels, the prior art supercomputer system 100 further includes a plurality of fans 120 mounted to upper portions of corresponding computer cabinets 110. In operation, each of the fans 120 draws cooling air into the corresponding computer cabinet 110 through a front inlet 114 and/or a back inlet 115 positioned toward a bottom portion of the computer cabinet 110. The cooling air flows upwardly through the computer cabinet 110, past the computer modules 112, and into the fan 120. The cooling air then flows out of the fan 120 and into the surrounding room.
One problem associated with the prior art supercomputer system 100 is the uneven distribution of heat in the computer cabinet 110. For example, the different computer modules 112 typically carry different arrangements of electronic devices depending on the particular application. The different devices can operate at different temperatures due to their varying power consumption. As a result, as the cooling air flows past the computer modules 112, high-power devices transfer more heat to the cooling air than low-power devices. The uneven heat transfer causes the cooling air to have uneven temperature profiles in the computer cabinet 110. As a consequence, the high temperature cooling air may not sufficiently cool some of the electronic devices due to its reduced heat capacitance.
One example of a conventional technique for improving cooling in a computer system uses a re-circulating water cooling system. FIG. 2, for example, illustrates a prior art computer system 230 having a water-cooled processing device 232. In the illustrated example, some external panels of the computer system 230 have been removed for clarity. The computer system 230 includes a computer module 236 (e.g., a motherboard) mounted in a housing 234 having a grill 235. The processing device 232 is mounted to the computer module 236. The computer system 230 further includes a heat exchanger 238 mounted on top of the processing device 232, a radiator 240 positioned proximate to the grill 235, a fan 244 positioned proximate to the radiator 240, and a circulating pump 241. The computer system 230 can optionally include a reservoir (not shown). The heat exchanger 238 is connected to the radiator 240 via out and return water lines 242a and 242b, respectively.
In operation, heat flows from the processing device 232 into the water circulating through the heat exchanger 238. The pump 241 moves the heated water from the heat exchanger 238 to the radiator 240. The fan 244 moves cooling air through the radiator 240 to cool the heated water. The pump 241 then re-circulates the cooled water back to the heat exchanger 238 via the water line 242a in a continuous cooling cycle.
There are a number of shortcomings associated with the re-circulating type water cooling system described above. For example, the heat exchanger 238 and the radiator 240 occupy a considerable amount of space in the housing 234. As a result, the housing 234 might not be able to accommodate additional processing devices if desired. Furthermore, the heat exchanger/radiator combination does not address the problem of uneven heat distribution. Consequently, some locations in the housing 234 might be at higher temperatures than others because of the arrangement of different heat-generating devices (e.g., video cards or memory chips) on the computer module 236.